Battery-operated stationary sensor arrangement with unidirectional data transmission

ABSTRACT

Embodiments of the present invention provide a battery-operated stationary sensor arrangement with a unidirectional data transmission. The battery-operated stationary sensor arrangement has a sensor, a means for generating data packets and a means for transmitting data packets. The transmitter is implemented to determine sensor data and provide a sensor data packet based on the sensor data, wherein the sensor data has an amount of data of less than 1 kbit. The means for generating data packets is implemented to divide the sensor data packet into at least two data packets, wherein each of the at least two data packets is shorter than the sensor data packet. The means for transmitting data packets is implemented to transmit the data packets with a data rate of less than 50 kbit/s and a time interval via a communication channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of copending InternationalApplication No. PCT/EP2012/066905, filed Aug. 30, 2012, which isincorporated herein by reference in its entirety, and additionallyclaims priority from German Patent Application No. 102011082098.1, filedSep. 2, 2011, which is also incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

Embodiments of the present invention relate to a battery-operatedstationary sensor arrangement with unidirectional data transmission.Further embodiments of the present invention relate to a hybrid methodfor a wireless transmission of burst-type data packets in a stationarymulti-user system.

In the transmission of small amounts of data, e.g. of sensor data of aheating, current or water meter, a radio transmission system may beused. Here, a measurement means with a data transmitter is attached tothe sensor which wirelessly transmits the sensor data to a datareceiver.

U.S. Pat. No. 7,057,525 B2 describes a system for a unidirectionalremote counter or meter readout having two means, one means whichgenerates short transmission packets for the mobile reception and onemeans which generates narrow-banded transmission packets receivableacross a larger distance from a stationary receiver. Here, the twosignals sent are only different with respect to signal bandwidth.

SUMMARY

According to an embodiment, a battery-operated stationary sensorarrangement with a unidirectional data transmission may have: a sensorfor determining sensor data and for providing a sensor data packet basedon the sensor data, the sensor data having an amount of data of lessthan 1 kbit; a means for generating data packets which is implemented todivide the sensor data packet into at least two data packets, whereineach of the at least two data packets is shorter than the sensor datapacket; and a means for transmitting data packets which is implementedto transmit the data packets with a data rate of less than 50 kbit/s anda time interval across the communication channel, wherein the means forgenerating data packets is implemented to divide a synchronizationsequence into partial synchronization sequences and to provide each datapacket with one of the partial synchronization sequences for asynchronization of the data packet in a data receiver.

According to another embodiment, a system may have a battery-operatedstationary sensor arrangement as mentioned above and a data receiver forreceiving the sensor data packet having: a means for receiving datapackets implemented to receive the at least two data packets and tocombine the at least two data packets and determine the sensor datapacket; and a means for reading out the sensor data packet implementedto determine the sensor data from the sensor data packet and to allocatethe sensor data to the battery-operated stationary sensor arrangement.

According to another embodiment, a method for transmitting a sensor datapacket in a battery-operated stationary sensor arrangement with aunidirectional data transmission may have the steps of: determiningsensor data with a sensor and providing a sensor data packet based onthe sensor data, wherein the sensor data has an amount of data of lessthan 1 kbit; generating data packets, wherein in the generation of datapackets the sensor data packet is divided into at least two datapackets, and wherein each of the at least two data packets is shorterthan the sensor data packet; and transmitting the at least two datapackets with a data rate of less than 50 kbit/s and a time interval viaa communication channel, wherein when generating data packets asynchronization sequence is divided into partial synchronizationsequences and each data packet is provided with one of the partialsynchronization sequences for a synchronization of the data packet in adata receiver.

Another embodiment may have a computer program having a program code forexecuting the above method for transmitting a sensor data packet, whenthe computer program is executed on a computer or microprocessor.

According to still another embodiment, a battery-operated stationarysensor arrangement with unidirectional data transmission may have: asensor for determining sensor data and for providing a sensor datapacket based on the sensor data, wherein the sensor data has an amountof data of less than 1 kbit; a means for generating data packetsimplemented to divide the sensor data packet into at least three datapackets, wherein each of the at least three data packets is shorter thanthe sensor data packet; and a means for transmitting data packetsimplemented to transmit the data packets with a data rate of less than50 kbit/s and a time interval via a communication channel; wherein themeans for generating data packets is implemented to channel-encode theat least three data packets such that only a part of the data packets isnecessitated for decoding the sensor data packet.

According to another embodiment, a battery-operated stationary sensorarrangement with unidirectional data transmission may have: a sensor fordetermining sensor data and for providing a sensor data packet based onthe sensor data, wherein the sensor data has an amount of data of lessthan 1 kbit; a means for generating data packets implemented to dividethe sensor data packet into at least two data packets, each of the atleast two data packets being shorter than the sensor data packet; and ameans for transmitting data packets implemented to transmit the datapackets with a data rate of less than 50 kbit/s and a time interval viaa communication channel; wherein the means for generating data packetsis implemented to additionally divide the sensor data packet into atleast three data packets, each of the at least three data packets beingshorter than the sensor data packet; and the means for transmitting datapackets being implemented to transmit the at least two data packets witha first transmission frequency via the communication channel and totransmit the at least three data packets with a second transmissionfrequency via the communication channel.

The present invention provides a battery-operated stationary sensorarrangement with a unidirectional data transmission. Thebattery-operated stationary sensor arrangement comprises a sensor, ameans for generating data packets and a for transmitting data packets.The sensor is implemented to determine sensor data and to provide asensor data packet based on the sensor data, wherein the sensor datacomprises an amount of data of less than one kbit. The means forgenerating data packets is implemented to divide the sensor data packetinto at least two data packets, wherein each of the at least two datapackets is shorter than the sensor data packet. The means fortransmitting data packets is implemented to transmit the data packetsvia a communication channel with a data rate of less than 50 kbit/s anda time interval.

In embodiments, the sensor data packet is divided into at least two datapackets, wherein the data packets are transmitted across thecommunication channel with a data rate of less than 50 kbit/s and a timeinterval. As compared to a conventional battery-operated stationarysensor arrangement wherein the sensor data packet is transmitted via thecommunication channel with a data rate of e.g. 100 kbit/s, the SNR ratio(signal to noise ratio) at the data receiver is increased and thus alsothe range is increased. Apart from that, by dividing the sensor datapacket into the at least two data packets and by the transmission of theat least two data packets via the communication channel with a timeinterval, on the one hand battery load and on the other handtransmission error probability are reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be explained in more detailbelow with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram of a battery-operated stationary sensorarrangement with a unidirectional data transmission according to oneembodiment of the present invention;

FIG. 2 is a block diagram of a system with a battery-operated stationarysensor arrangement and a data receiver according to one embodiment ofthe present invention;

FIG. 3 is a block diagram of a data receiver according to one embodimentof the present invention;

FIG. 4 is a schematic illustration of a distribution of data packets todifferent transmission frequencies according to one embodiment of thepresent invention;

FIG. 5 is a time capacity utilization of a communication channel withthe Aloha method;

FIG. 6 in a diagram, different possibilities for increasing E_(b)/N₀ ina transmission of a telegram according to one embodiment of the presentinvention;

FIG. 7 is a diagram of a probability of receiving a telegram as afunction of a normalized telegram length;

FIG. 8 is a time capacity utilization of a communication channel in atransmission of n data packets according to one embodiment of thepresent invention;

FIG. 9 is a diagram of a probability of a telegram error depending onthe number of data packets for f_(N)=20, D_(Σx)=0.2 andP(XF_(W))=2.3·10⁻¹⁰;

FIG. 10 is a diagram of the probability of a telegram error depending onthe number of data packets for f_(N)=20, D_(Σx)=0.5 andP(XF_(W))=1.0·10⁻⁴; and

FIG. 11 is a diagram of the probability of a telegram error depending onthe number of data packets for f_(N)=20, D_(Σx)=0.8 andP(XF_(W))=1.1·10⁻².

DETAILED DESCRIPTION OF THE INVENTION

In the following description of the embodiments of the invention, in thefigures like or seemingly like elements are provided with the samereference numerals, so that a description of the same in the differentembodiments is mutually interchangeable.

FIG. 1 shows a block diagram of a battery-operated stationary sensorarrangement 100 with a unidirectional data transmission. Thebattery-operated stationary sensor arrangement 100 comprises a sensor102, a means 104 for generating data packets and a means 106 fortransmitting data packets. The sensor 102 is implemented to determinesensor data and to provide a sensor data packet based on the sensordata, wherein the sensor data comprises an amount of data of less than 1kbit. The means 104 for generating data packets is implemented to dividethe sensor data packet into at least two data packets, wherein each ofthe at least two data packets is shorter than the sensor data packet.The means 106 for transmitting data packets is implemented to transmitthe data packets with a data rate of less than 50 kbit/s and a timeinterval across a communication channel.

In embodiments, for increasing the range, the sensor data is transmittedin a narrow-banded way with a data rate of less than 50 kbit/s, e.g. 40kbit/s, 30 kbit/s, 20 kbit/s or 10 kbit/s instead of, e.g., a data rateof 100 kbit/s. In a system 110 with a battery-operated, stationarysensor arrangement 100 (data transmitter) with a unidirectional datatransmission (i.e. without reverse channel) and a data receiver 120, ase.g. illustrated in FIG. 2, the SNR ratio at the data receiver 120increases and thus also the range increases. As a consequence, however,the bit duration increases and thus the transmitted energy per bitincreases in the inventive system 110 with the low data rate. As thebattery in the system 110 may not be put under load for a long time butmay only provide a higher power for a short time, the longer bitduration is a problem. In order to guarantee a long battery lifetimeonly short bursts ought to be sent out. This is why the narrow-bandedsensor data packet is divided into smaller data packets (partialpackets) in order to only have a short pulse-type load of the battery.Further, the data packets may be channel-coded, e.g. such that not alldata packets but only a certain portion is necessitated for decoding theinformation.

The sensor 102 of the battery-operated stationary sensor arrangement 100may be a sensor or counter, like e.g. a temperature sensor, heating,current or water counter or meter, wherein the sensor data may be asensor value or counter reading. The inventive system 110 with thebattery-operated stationary sensor arrangement 100 (data transmitter)and the data receiver 120 comprises no reverse channel. The datatransmitter 100 may here send out the sensor data at a pseudorandomtime, wherein the data receiver 120 may receive sensor data from several(different) data transmitters 100.

FIG. 3 shows a block diagram of a data receiver 120 according to oneembodiment of the present invention. The data receiver 120 comprises ameans 122 for receiving data packets and a means 124 for reading out thesensor data packet. The means 122 for receiving data packets isimplemented to receive the at least two data packets and to combine theat least two data packets in order to determine the sensor data packet.The means 124 for reading out the sensor data packet is implemented todetermine the sensor data from the sensor data packet and to allocatethe sensor data to the battery-operated stationary sensor arrangement100.

For the synchronization of the data packet in the data receiver 120 themeans 104 for generating data packets of the battery-operated stationarysensor arrangement 100 may be implemented to divide a synchronizationsequence into partial synchronization sequences in order to provide eachdata packet with one of the partial synchronization sequences.

The means 122 for receiving the data packets of the data receiver 120may here be implemented to localize the data packets in a received datastream based on the partial synchronization sequences in order toreceive the data packets.

For the synchronization of the data packets in the data receiver 120thus synchronization sequences may be utilized. Synchronizationsequences are deterministic or pseudorandom binary data sequences, e.g.PRBS sequences (pseudo random bitstream), which are transmitted togetherwith the actual payload data or sensor data in the data packets to thedata receiver 120. The data receiver 120 knows the synchronizationsequences. By a correlation of the receive data stream with the knownsynchronization sequence the data receiver 120 may determine thetemporal position of the known synchronization sequence in the receivedata stream. Here, the correlation function comprises a correlation peakat the location of the synchronization sequence in the receive datastream, wherein the higher or greater the peak the better the receivedata stream corresponds to the known synchronization sequence. Tofurther keep the burst-type data packets short, for a synchronizationalso the synchronization sequence may be distributed across theindividual short data packets, so that the individual data packet showsworse synchronization characteristics than the synchronization acrossseveral data packets. In order to utilize this synchronization effect,the points in time of the consecutive data packets may be known to thedata receiver 120. Alternatively, the means for receiving the datapackets of the data receiver 120 may be implemented to determine thetime interval or temporal distance of the data packets based on thepartial synchronization sequences in order to localize the partialsynchronization sequence in the receive data stream. As the datatransmitter 100 and the data receiver 120 are stationary and thus remainunchanged across a long period of time, the data receiver 120 may beimplemented to determine the time sequence of the data packets bylearning methods.

The means 104 for generating data packets of the battery-operatedstationary sensor arrangement 100 may be implemented to additionallydivide the sensor data packet into at least three data packets, whereineach of the at least three data packets is shorter than the sensor datapacket. Further, the means 106 for transmitting data packets of thebattery-operated stationary sensor arrangement 100 may be implemented totransmit the at least two data packets with a first transmit frequencyacross the communication channel and to transmit the at least three datapackets with a second transmit frequency across the communicationchannel.

The means 122 for receiving the data packets of the data receiver 120may here be implemented to receive the at least two data packets on afirst transmit frequency and/or to receive the at least three datapackets on the second transmit frequency and to combine the at least twodata packets and/or the at least three data packets in order todetermine the sensor data packet.

The means 104 for generating data packets of the battery-operatedstationary sensor arrangement 100 may further be implemented to encodethe at least two data packets with a first code rate (information rate)and to encode the at least three data packets with a second code rate(information rate), wherein the first code rate is larger than thesecond code rate.

In order to additionally be robust against interferences or existing orother systems, the data packets may be distributed to differenttransmission frequencies or transmit frequencies (channels). Forexample, the data packets may be distributed to n=2, n=3, n=4, n=5, n=10or n=20 channels.

FIG. 4 shows a schematic illustration of a distribution of data packetsonto different transmit frequencies according to one embodiment of thepresent invention. In FIG. 4, the data packets are exemplarily dividedinto three transmit frequencies or frequency channels. The telegram tobe transmitted (sensor data packet) for example comprises an amount ofdata of 75 bytes, wherein the data packets are for example transmittedwith a data rate of 20 kbit/s across the communication channel. Thelength of each data packet here for example is 10 ms (=200 bits), fromwhich an overall telegram length of 220 s (update rate approximately 4minutes) results.

In the embodiment illustrated in FIG. 4, the means 104 for generatingdata packets of the battery-operated stationary sensor arrangement 100is implemented to divide the sensor data packet into 12 data packets inorder to additionally divide the sensor data packet into 6 data packetsand to additionally divide the sensor data packet into 4 data packets.Further, the means 106 for transmitting the data packets of thebattery-operated stationary sensor arrangement 100 is implemented totransmit the 4 data packets on a first transmission frequency (channel1), the 6 data packets on a second transmission frequency (channel 2)and the 12 data packets on a third transmission frequency (channel 3).

Further, the data in the individual channels may be encoded differentlyin order to be optimal for different application scenarios. Thus, e.g.channel 3 may be encoded with a rate of ¼ and data packets are morefrequently transmitted on this channel than in channel 1 by lessfrequently transmitting with a higher code rate of e.g. ¾. Withinterferences in one or the other channel it would be possible to stilldecode the respective other channel. In the non-interfered case, thedata packets of all channels would be MLE decoded (MLE=maximumlikelihood estimation). In a rural environment where the transmitterdensity is lower, using the code rate and the high packet transmissionrate a high range could be acquired. If the transmitter densityincreases, in this channel an increase in collision and interferencesresults. With high transmitter densities in an urban environment, thelower transmission rate in channel 1 would lead to less collisions butalso to a decreased range due to the higher code rate. With hightransmitter densities, however, no high range is required, as due to themany collisions a load-conditioned range limitation results.Load-conditioned range limitation means that due to the occurringcollisions the stronger near data transmitters (better signal-to-noiseratio) are encoded and the more remote weaker data transmitters aresuperimposed. It may be an advantage in embodiments to transmit with alower code rate with higher transmitter densities, even if this resultsin a higher latency.

In the following, the improvements and advantages of the presentinvention as compared to known technology are explained in more detail.

FIG. 5 shows a temporal capacity utilization of a communication channelwith the Aloha method. Here, the abscissa describes the time and theordinate describes the frequency. In the Aloha method payload data istransmitted in so-called telegrams divided into one or several datapackets in one channel from a data transmitter. Further, in the samechannel n=0 other data transmitters X_(i), X_(j) and X_(k), with iε{1, .. . , n}, jε{1, . . . , n} and kε{1, . . . , n} also transmit datapackets. If the transmission of one data packet of one data transmitterX temporally overlaps sending out a data packet from data transmitter A,then as illustrated in FIG. 5 the transmission of the data packet fromthe data transmitter A is interfered or disturbed. Sending out datapackets of the data transmitters C would happen randomly.

The length of the data packets of the data transmitter A is assumed tobe T_(A), the one of the data transmitters X_(i) is assumed to beT_(X,i). The channel occupation of one individual data transmitter X_(i)is defined by the so-called duty cycle of the respective datatransmitter D_(X,i)=τ/Tε[0,1] as a ratio of transmission time τ tooperating time T. A data transmitter may here take on the transmitterstate S is on (1) or off (0), i.e. Sε{0,1}. The probability for anundisturbed transmission may be approximated to be

${P\left( A_{A} \right)} = {^{- \frac{{({T_{A} + T_{X}})}D_{\Sigma \; X}}{T_{X}}}.}$

Here, D_(Σx)=kD_(X) is the sum duty cycle of the interfering ordisturbing data transmitter X.

For receiving a transmission, at the data receiver 120 in principle aE_(b)/N₀ depending on the used modulation and channel encoding isnecessitated. E_(b) here designates the energy per bit, N₀ designatesthe noise performance density, the performance of noise in a normalizedbandwidth. The SNR ratio (signal to noise ratio) is defined as follows

${SNR} = \frac{S}{N}$

with the signal energy S and the noise performance N. The noiseperformance (noise power) here relates to a certain bandwidth, N=BN₀applies with the bandwidth B. The signal performance is calculated to beS=E_(B)D. Thus the following applies

$\frac{E_{b}}{N_{0}} = {\frac{S}{N}\frac{B}{D}}$ or$\frac{S}{N} = {\frac{E_{b}}{N_{0}}\frac{D}{B}}$

with the data rate D. With an increasing distance of the data receiver120 to the data transmitter A, usually the received energy per bit E_(b)decreases. In order to now increase the range of a transmission, inprinciple different possibilities are available.

For example, transmission performance may be increased, whereby also theenergy per bit E_(b) is increased, which may not frequently be appliedfrom a regulatory view. Further, a modulation or channel encoding with alow E_(b)/N₀ may be used, wherein this is limited by the Shannon limit.Alternatively, the transmission duration of the telegram (sensor datapacket) may be increased, whereby the data rate is reduced and theenergy per bit E_(b) is increased which is the starting point describedin the following.

In a diagram, FIG. 6 shows different possibilities for increasingE_(b)/N₀ in a transmission of a telegram (sensor data packet) accordingto one embodiment of the present invention. Here, the abscissa describesthe time and the ordinate describes the frequency. A decrease of thedata rate of the data transmitter A, as illustrated in FIG. 6, may becaused by a lower symbol rate (transmitter B) or by the use of a lowercode rate (transmitter C) or a combination of both ways (transmitter D).By this, the necessitated time for the transmission is longer, and thedata transmitter 100 may emit more energy with the same transmissionperformance and a longer transmission time.

For example, the means for transmitting the data packets may beimplemented to provide the data packets with a symbol rate of less than1·10⁶ symbol/s or also less than 5·10⁵ symbol/s, 3·10⁵ symbol/s, 2·10⁵symbol/s or 1·10⁵ symbol/s and/or a code rate of less than 0.8 or alsoless than 0.5, 0.3, 0.25 or 0.1.

If a lower code rate is used, in general for a transmission a smallerE_(b)/N₀ is necessitated. However, the necessitated bandwidth increasesas compared to the use of a slower modulation. In all outlined cases,transmission is lengthened. In case of reducing the symbol rate with

${P\left( A_{A} \right)} = ^{- \frac{{({T_{A} + T_{X}})}D_{\Sigma \; X}}{T_{X}}}$

this leads to a reduction of the transmission probability.

FIG. 7 shows a diagram of a probability of receiving a telegram (sensordata packet) as a function of a normalized telegram length. Here, theabscissa describes the normalized telegram length f_(N) withf_(N)=T_(A)/T_(X) and the ordinate describes the probability P(A) ofreceiving the telegram.

A first curve 150 describes the probability P(A) of receiving thetelegram (sensor data packet), for D_(ΣX)=0.05; a second curve 152describes the probability P(A) of receiving the telegram for D_(ΣX)),=0.10; a third curve 154 describes the probability P(A) of receiving thetelegram for D_(ΣX)), =0.15; a fourth curve 156 describes theprobability P(A) of receiving the telegram for D_(ΣX)), =0.20; and afifth curve 158 describes the probability P(A) of receiving the telegramfor D_(ΣX)=0.30.

It may be seen in FIG. 7 that the probability P(A) of receiving thetelegram (sensor data packet) decreases with an increasing telegramlength. Further, the probability P(A) of receiving the telegramdecreases with an increasing sum duty cycle D_(ΣX). For increasing therange, however, a lengthening of the transmission duration of thetelegram (sensor data packet) or a reduction of the data rate isnecessitated.

In embodiments, the sensor data packet is divided into at least two datapackets, wherein the data packets are transmitted with a data rate ofless than 50 kbit/s and a time interval or time distance across thecommunication channel. By dividing the sensor data packet into the atleast two data packets and by the transmission of the at least two datapackets via the communication channel with a time interval, on the onehand battery load and on the other hand transmission error probabilityare reduced, as it is explained in the following.

The telegram (sensor data packet), as for example illustrated in FIG. 8,may be transmitted with the help of several n (of equal size) datapackets. If an ideal code is assumed, at the data receiver 120, whenusing the Code Rate c, at least ┌cn┐ data packets have to be receivederror-free so that the telegram (sensor data packet) may bereconstructed error-free. Here, using the packet error probability P(PF)the probability for a telegram error P(TF) with p=1−P(PF) is calculatedto be

${P({TF})} = {{P\left( {X < \left\lceil {cn} \right\rceil} \right)} = {\sum\limits_{k = 0}^{{\lceil{cn}\rceil} - 1}\; {\left( {1 - p} \right)^{n - k}{p^{k}\begin{pmatrix}n \\k\end{pmatrix}}}}}$

For the following considerations it is assumed that the transmitted datapackets were transmitted at random times. It is further assumed in thefollowing that a system X is already in operation. The transmissions areto be random, the amount of data is assumed to be constant for all datatransmitters of the system X, T_(X) is the transmission duration of eachdata transmitter of the system X. D_(ΣX) is the summed up duty cycle ofall data transmitters of the system X.

Now a further data transmitter A is to be operated, wherein the datatransmitter A relates to the battery-operated stationary sensorarrangement 100. The data transmitter A is disturbed by transmissions ofthe existing system X. The data transmitter A is to transmit the sameamount of data as in system X and use the same modulation.

The range of the data transmitter A with respect to the existing systemX is to be increased by increasing E_(b) by the factor f_(N). Thus, thetransmission duration of the telegram is lengthened by the factor f_(N).A telegram is transmitted divided into n individual data packets. T_(T)is the complete transmission duration of a telegram, T_(P)=T_(T)/n isthe transmission duration of a data packet. Thus, the following resultsfor the packet error rate

${P({PF})} = {{1 - ^{- \frac{{({T_{P} + T_{X}})}D_{\Sigma \; X}}{T_{X}}}} = {{1 - ^{- \frac{{({\frac{T_{T}}{n} + T_{X}})}D_{\Sigma \; X}}{T_{X}}}} = {{1 - ^{\frac{{({\frac{{fT}_{X}}{n} + T_{X}})}D_{\Sigma \; X}}{T_{X}}}} = {1 - {^{{- {({\frac{f_{N}}{n} + 1})}}D_{\Sigma \; X}}.}}}}}$

According to this, the probability of a packet error increases with ahigher f_(N) and decreases with a higher n, it is independent of thecode rate c.

A data transmitter of the system X may transmit f_(N) telegrams duringthe transmission time which the data transmitter A necessitates for atelegram. By this, the probability increases that a telegram of atransmitter X may be transmitted in the time in which the datatransmitter A transmits a telegram.

The probability for the data transmitter X with f_(N) transmittedtelegrams, each of which has an error probability of P(XF), to receivenone of them, like with the repetition code, is calculated to be

P(XF _(W))=P(XF)^(f) ^(N) .

The bandwidth of the data transmitter A normalized to the datatransmitters of system X is calculated to be

$b_{N} = {\frac{f_{N}}{c}.}$

FIG. 9 shows a diagram of a probability of a telegram error depending onthe number of data packets for f_(N)=20, D_(ΣX)=0.2 undP(XF_(W))=2.3·10⁻¹⁰. A first curve 160 describes the probability of atelegram error for c=1 and b_(N)=0.05; a second curve 162 describes theprobability of a telegram error for c=0.5 and b_(N)=0.1; a third curve164 describes the probability of a telegram error for c=0.33 andb_(N)=0.15; a fourth curve 166 describes the probability of a telegramerror for c=0.25 and b_(N)=0.20; a fifth curve 168 describes theprobability of a telegram error for c=0.13 and b_(N)=0.4; and a sixthcurve 170 describes the packet error rate P(PF).

FIG. 10 shows a diagram of a probability of a telegram error dependingon the number of data packets for f_(N)=20, D_(ΣX)=0.5 undP(XF_(W))=1.0·10⁻⁴. A first curve 172 describes the probability of atelegram error for c=1 and b_(N)=0.05; a second curve 174 describes theprobability of a telegram error for c=0.5 and b_(N)=0.1; a third curve176 describes the probability of a telegram error for c=0.33 andb_(N)=0.15; a fourth curve 178 describes the probability of a telegramerror for c=0.25 and b_(N)=0.20; a fifth curve 180 describes theprobability of a telegram error for c=0.13 and b_(N)=0.4; and a sixthcurve 182 describes the packet error rate P(PF).

FIG. 11 shows a diagram of a probability of a telegram error dependingon the number of data packets for f_(N)=20, D_(ΣX)=0.8 andP(XF_(W))=1.1·10⁻². A first curve 184 describes the probability of atelegram error for c=1 and b_(N)=0.05; a second curve 186 describes theprobability of a telegram error for c=0.5 and b_(N)=0.1; a third curve188 describes the probability of a telegram error for c=0.33 andb_(N)=0.15; a fourth curve 190 describes the probability of a telegramerror for c=0.25 and b_(N)=0.20; a fifth curve 192 describes theprobability of a telegram error for c=0.13 and b_(N)=0.4; and a sixthcurve 194 describes the packet error rate P(PF).

It may be seen in FIGS. 9 to 11, that dividing the telegram (sensor datapacket) into at least two data packets protected by a forward errorcorrection code increases the transmission probability. This may also beconsidered under the aspect “time diversity”. This is the basis of theinventive concept to provide the telegram or sensor data packet with aforward error correction and divide the same into at least two datapackets and transmit the same at pseudo random times. Here, thetransmissions of the battery-operated stationary sensor arrangement 100are made longer (decreased data rate) in order to increase the range.Using the outlined method the usually accompanying decrease oftransmission security is counteracted.

In embodiments, thus the range is increased by a more narrow-bandedtransmission and additional channel encoding. Further, for improvingtransmission security (interference by other systems) and for adecreased load of the battery the narrow banded sensor data packets aredivided into several short data packets. The data packets mayadditionally also be transmitted on different frequency bands (frequencyhopping). Apart from this, for a better synchronization shortsynchronization sequences are used.

Further embodiments of the present invention provide a method fortransmitting a sensor data packet in a battery-operated stationarysensor arrangement with a unidirectional data transmission. In a firststep, sensor data is determined with a sensor and a sensor data packetis provided based on the sensor data, wherein the sensor data comprisesan amount of data of less than 1 kbit. In a second step, data packetsare generated, wherein in the generation of data packets, the sensordata packet is divided into at least two data packets and wherein eachof the at least two data packets is larger than the sensor data packet.In a third step, the at least two data packets are transmitted with adata rate of less than 50 kbit/s and a time interval across acommunication channel.

Further embodiments of the present invention relate to a wireless,unidirectional transmission method for fields of application with astationary data transmitter 100 and a stationary data receiver 120,wherein the data receiver has a comparatively longer time to receive thedata.

Although some aspects were described in connection with a device, it isobvious that those aspects also represent a description of thecorresponding method, so that a block or a member of a device may alsobe regarded as a corresponding method step or as a feature of a methodstep. Analog to this, aspects which were described in connection with oras a method step also represent a description of a corresponding blockor detail or feature of a corresponding device. Some or all of themethod steps may be executed by a hardware apparatus (or using ahardware apparatus), like, for example, a microprocessor, a programmablecomputer or an electronic circuit. In some embodiments, some or severalof the most important method steps may be executed by such an apparatus.

Depending on certain implementation requirements, embodiments of theinvention may be implemented in hardware or in software. Theimplementation may be executed using a digital storage medium, forexample a floppy disc, a DVD, a Blu-Ray disc, a CD, an ROM, a PROM, aEPROM, an EEPROM or a FLASH memory, a hard disc or another magnetical oroptical memory on which electronically readable control signals arestored which may cooperate or do cooperate with a programmable computersystem such that the respective method is executed. Thus, the digitalstorage medium may be computer-readable.

Some embodiments according to the invention thus include a data carrierwhich comprises electronically readable control signals which are ableto cooperate with a programmable computer system such that one of themethods described herein is executed.

In general, embodiments of the present invention may be implemented as acomputer program product with a program code, wherein the program codeis operable in order to execute one of the methods when the computerprogram product is executed on a computer.

The program code may, for example, be stored on a machine-readablecarrier.

Other embodiments include the computer program for executing one of themethods described herein, wherein the computer program is stored on amachine-readable carrier. In other words, an embodiment of the inventivemethod is thus a computer program comprising a program code forexecuting one of the methods described herein when the computer programis executed on a computer.

A further embodiment of the inventive method thus is a data carrier (ora digital storage medium or a computer-readable medium) on which thecomputer program for executing one of the methods described herein isrecorded.

A further embodiment of the inventive method thus is a data stream or asequence of signals which, for example, represent the computer programfor executing one of the methods described herein. The data stream orthe sequence of signals may, for example, be configured so as to betransferred via a data communication connection, for example via theinternet.

A further embodiment includes a processing means, for example a computeror a programmable logic device configured or adapted to execute one ofthe methods described herein.

A further embodiment includes a computer on which the computer programfor executing one of the methods described herein is installed.

A further embodiment according to the invention includes a device or asystem which is implemented to transmit a computer program for executingat least one of the methods described herein to a receiver. Thetransmission may be executed, for example, electronically or optically.The receiver may, for example, be a computer, a mobile device, a memorydevice or a similar device. The device or the system may, for example,be a file server for transmitting the computer program to the receiver.

In some embodiments, a programmable logic device (for example a fieldprogrammable gate array, an FPGA) may be used to execute some or allfunctionalities of the method described herein. In some embodiments, afield-programmable gate array may cooperate with a microprocessor inorder to execute one of the methods described herein. In general, insome embodiments the methods are executed by any hardware device. Thesame may be a universally usable hardware like a computer processor(CPU) or hardware which is specific for the method, like, for example,an ASIC.

While this invention has been described in terms of several embodiments,there are alterations, permutations, and equivalents which will beapparent to others skilled in the art and which fall within the scope ofthis invention. It should also be noted that there are many alternativeways of implementing the methods and compositions of the presentinvention. It is therefore intended that the following appended claimsbe interpreted as including all such alterations, permutations, andequivalents as fall within the true spirit and scope of the presentinvention.

1. (canceled)
 2. A method for unidirectional data transmission, themethod comprising: determining sensor data; providing a sensor datapacket based on the sensor data, the sensor data comprising an amount ofdata of less than 1 kbit; generating data packets, wherein generatingdata packets comprises dividing the sensor data packet into at leastthree data packets, wherein each of the at least three data packets isshorter than the sensor data packet; and transmitting the data packetswith a data rate of less than 50 kbit/s and a time interval across thecommunication channel, wherein generating the data packets compriseschannel-encoding the at least three data packets such that only a partof the data packets is required for decoding the sensor data packet. 3.The method according to claim 2, wherein transmitting the data packetscomprises selecting the time interval of the data packets such that abattery load of a battery-operated stationary sensor arrangement isreduced.
 4. The method according to claim 2, wherein transmitting thatdata packets comprises providing the data packets with a symbol rate ofless than 106 symbols and/or a code rate of less than 0.8.
 5. The methodaccording to claim 2, wherein generating data packets comprises dividingthe sensor data packet additionally into at least two data packets,wherein each of the at least two data packets is shorter than the sensordata packet; and wherein transmitting data packets comprisestransmitting the at least two data packets with a first transmissionfrequency via the communication channel and to transmitting the at leastthree data packets with a second transmission frequency via thecommunication channel.
 6. The method according to claim 5, whereingenerating data packets comprises encoding the at least two data packetswith a first code rate and encoding the at least three data packets witha second code rate, wherein the first code rate is higher than thesecond code rate.
 7. The method according to claim 2, wherein generatingdata packets comprises distributing a synchronization sequence acrossthe data packets, so that an individual data packet shows worsesynchronization characteristics than the synchronization across severaldata packets.
 8. The method according to claim 2, wherein transmittingdata packets comprises distributing the data packets to differenttransmission frequencies, in order to be robust against interferences orexisting or other systems.
 9. The method according to claim 2, themethod further comprising: receiving data packets, wherein receivingdata packets comprises receiving at least two data packets and combiningthe at least two data packets and determine the sensor data packet; andreading out the sensor data packet to determine the sensor data from thesensor data packet and to allocate the sensor data to a battery-operatedstationary sensor arrangement.
 10. The method according to claim 9,wherein generating data packets comprises distributing a synchronizationsequence across the data packets, so that an individual data packetcomprises a partial synchronization sequence and shows worsesynchronization characteristics than the synchronization across severaldata packets; and wherein receiving the data packets compriseslocalizing the data packets in a receive data stream based on thepartial synchronization sequences in order to receive the data packets.11. The method according to claim 10, wherein receiving data packetscomprises determining the time interval of the data packets based on thepartial synchronization sequences to localize the partialsynchronization sequences in the receive data stream.
 12. The methodaccording to claim 9, wherein the sensor data packet is transmitteddivided into at least two data packets with a first transmissionfrequency and, in addition, is transmitted divided into at least threedata packets with a second transmission frequency via the communicationchannel; wherein receiving the data packets comprises at least one outof receiving the at least two data packets on a first transmissionfrequency and receiving the at least three data packets on the secondtransmission frequency; and wherein receiving the data packets comprisesat least one out of combining the at least two data packets andcombining the at least three data packets, in order to determine thesensor data packet.
 13. The method according to claim 12, wherein the atleast two data packets encoded with a first code rate and the at leastthree data packets encoded with a second code rate are transmitted viathe communication channel; wherein receiving the data packets comprisesat least one out of decoding the at least two data packets and decodingthe at least three data packets.
 14. A non-transitory computer-readablemedium including a computer program having a program code for executingthe method according to claim 2, when the computer program is executedon a computer or microprocessor.
 15. A method for unidirectional datatransmission, the method comprising: determining sensor data with asensor; providing a sensor data packet based on the sensor data, whereinthe sensor data comprises an amount of data of less than 1 kbit;generating data packets, wherein generating data packets comprisesdividing the sensor data packet into at least two data packets, andwherein each of the at least two data packets is shorter than the sensordata packet; and transmitting the data packets with a data rate of lessthan 50 kbit/s and a time interval via a communication channel, whereingenerating data packets comprises distributing a synchronizationsequence across the data packets, so that an individual data packetshows worse synchronization characteristics than the synchronizationacross several data packets.
 16. A non-transitory computer-readablemedium including a non-transitory computer-readable medium including acomputer program having a program code for executing the methodaccording to claim 15, when the computer program is executed on acomputer or microprocessor.
 17. A method for unidirectional datatransmission, the method comprising: determining sensor data; providinga sensor data packet based on the sensor data, wherein the sensor datacomprises an amount of data of less than 1 kbit; generating datapackets, wherein generating data packets comprises dividing the sensordata packet into at least two data packets, wherein each of the at leasttwo data packets is shorter than the sensor data packet; andtransmitting the data packets with a data rate of less than 50 kbit/sand a time interval via a communication channel; wherein generating datapackets comprises dividing the sensor data packet additionally into atleast two data packets, wherein each of the at least two data packets isshorter than the sensor data packet; and wherein transmitting datapackets comprises transmitting the at least two data packets with afirst transmission frequency via the communication channel and totransmitting the at least three data packets with a second transmissionfrequency via the communication channel.
 18. A non-transitorycomputer-readable medium including a computer program having a programcode for executing the method according to claim 17, when the computerprogram is executed on a computer or microprocessor.
 19. Abattery-operated stationary sensor arrangement for performing anunidirectional data transmission, comprising: a sensor for determiningsensor data and for providing a sensor data packet based on the sensordata, wherein the sensor data comprises an amount of data of less than 1kbit; a means for generating data packets implemented to divide thesensor data packet into at least three data packets, wherein each of theat least three data packets is shorter than the sensor data packet; anda means for transmitting data packets implemented to transmit the datapackets with a data rate of less than 50 kbit/s and a time interval viaa communication channel; wherein the means for generating data packetsis implemented to channel-encode the at least three data packets suchthat only a part of the data packets is required for decoding the sensordata packet.
 20. A battery-operated stationary sensor arrangement withunidirectional data transmission, comprising: a sensor for determiningsensor data and for providing a sensor data packet based on the sensordata, wherein the sensor data comprises an amount of data of less than 1kbit; a means for generating data packets implemented to divide thesensor data packet into at least two data packets, wherein each of theat least two data packets is shorter than the sensor data packet; and ameans for transmitting data packets implemented to transmit the datapackets with a data rate of less than 50 kbit/s and a time interval viaa communication channel; wherein the means for generating data packetsis implemented to distribute a synchronization sequence across the datapackets, so that an individual data packet shows worse synchronizationcharacteristics than the synchronization across several data packets.21. A battery-operated stationary sensor arrangement for performing anunidirectional data transmission, comprising: a sensor for determiningsensor data and for providing a sensor data packet based on the sensordata, wherein the sensor data comprises an amount of data of less than 1kbit; a means for generating data packets implemented to divide thesensor data packet into at least two data packets, each of the at leasttwo data packets being shorter than the sensor data packet; and a meansfor transmitting data packets implemented to transmit the data packetswith a data rate of less than 50 kbit/s and a time interval via acommunication channel; wherein the means for generating data packets isimplemented to additionally divide the sensor data packet into at leastthree data packets, each of the at least three data packets beingshorter than the sensor data packet; and the means for transmitting datapackets being implemented to transmit the at least two data packets witha first transmission frequency via the communication channel and totransmit the at least three data packets with a second transmissionfrequency via the communication channel.